Lymphocytes Flashcards
(37 cards)
Severe combined immunodeficiency babies
Inability to clear infections
What does the adaptive immune system do
Improves the efficacy of the innate immune response
Focuses a response on the site of infection and the organism responsible
Has memory
Needs time to develop
Why type of response is T cells
Cell mediated response
What type of response is B cell
Humoral Response
What do the T cells do
Cytokines help shape immune response (CD4)
Kill infected cells (CD8)
What do the B cells do
Produce antibodies
Antigens
Moelcules that induce an adaptive immune response
What is the epitope
Region of an antigen which the receptor binds to
What type of antigen do T cells recognise
Linear epitopes in the context of MHC
Primary structure
What type of antigen does B cell recognise
Structural epitopes (3D structure)
Folding
What is clonal expansion
Interaction between a foreign molecule and that receptor leads to activation and clonal expansion
Differentiated effector cells will bear the same receptor
What is the antigen receptor diversity problem
Massive repertoire of lymphocytes receptors
Massive genes neeeded
How is antigen receptor diveristy generated through recombination
Functional genes for antigen receptors do not exist until generated during lymphocyte development
Immunoglobulin gene rearrangement
V and J area combined randomly and may sometimes overlap
Diagram of the T cell receptor
Recognises antigen fragments presented by other cells in the context of MHC
What is the major histocompatibility complex
Plays a central role in defining self and not self
Presents antigens to T cells
What is the MHC class 1
All nucleated cells
Single variable alpha chain plus a common beta microglobulin
What is the MHC class 2 complex
Only on professional antigen presenting cells
2 chains alpha and beta
Is the MHC polygenic
3 Class 1 loci and 3 class 2 loci
Expression is codominant
Why is matching people to surgery so important in MHC
Because each person can have up to 6 of each gene if completely heterozygous
How is the MHC1 complex loaded with antigen
Comes from intracellular pathogen
How is the MHC2 complex loaded with antigen
Extracellular antigen
How is the response to different pathogens orchastrated by the CD4 T helper cells
T helper cells produce cytokines
Cytokines have diverse actions on a wide range of cells
Th1 (pro-inflammatory, boost cellular immune reponse - fight off viruses)
Th2 (Pro-Allergic, boost muticellular repsonse)
What are Tfh
Pro-antibody
Works with B cells
IL-21
How do CD8 cells kill the targets
Programmed cell death - apoptosis
Fragmentation of nuclear DNA
CTL stores perforin, granzymes, granulysin in cytotoxic granules released after target recognition
Perforin - pore forming protein
Granzyme injected into cell through pores
